i´ve a RX/TX connection between two arduino boards. the TX unit is always sending serial data.sometimes the receiver goes standby (cause its hooked up to usb). so if its up again it receivesthe serial data immidiately and overwrites the programme inside because the bootloader isstarted. is there a possibility to burn via arduino without burning the bootloader on the chip (i´m awarethat this will only function one time!)

You'll need an external programmer like an AVR-ISP, STK500 or a homemade parallel port programmer:http://www.arduino.cc/en/Main/ParallelProgrammer

With those, you'll overwrite the bootloader with your program, allowing you to use the full 8 KB of program space (flash) on the ATmega8 (as well as avoiding the problem you're having). You'll be able to write to the chip as many times as you want. I don't think there's a way to overwrite the bootloader without an external programmer, as the bootloader segment is locked to avoid accidental overwrites.

In theory, you can use an Arduino board as an AVR-ISP to program another Arduino board, but we haven't quite gotten it working yet. If you have a Wiring board, you can use that as an AVR-ISP.

Is your AVR-ISP an older one or a MKII? If an older one, you can upload your sketch straight from the Arduino IDE. You just need to make three changes to the Arduino preferences.txt. Make sure to edit this file when the Arduino IDE is not running. First, change: serial.download_rate=19200 to serial.download_rate=115200. Then, change upload.erase and upload.verify from false to true. Afterwards, you'll need to change back those lines in preferences.txt.

If it's an AVRISPvII (or MKII or whatever it's called), you'll need to upload from the command line with avrdude or avrstudio (or a similar program). If you press upload in the Arduino IDE, the .hex file will appear in the "applet" sub-directory of the sketch folder (which you can find by selecting "Show Sketch Folder" from the "Sketch" menu). You should be able to use the .hex file unchanged.